When the cork hits the water, that energy travels through the water in waves. Students can measure the bowl beforehand to help them make a better estimation of the wavelength. Surface earthquake waves are similar to surface waves on water. The longitudinal waves in an earthquake are called pressure waves P-waves and the transverse waves are called shear waves S-waves. These two types of waves propagate at different speeds, and the speed at which they travel depends on the rigidity of the medium through which they are traveling.
During earthquakes, the speed of P-waves in granite is significantly higher than the speed of S-waves. Both components of earthquakes travel more slowly in less rigid materials, such as sediments. For that reason, the time difference between the P- and S-waves is used to determine the distance to their source, the epicenter of the earthquake. We know from seismic waves produced by earthquakes that parts of the interior of Earth are liquid.
In contrast, compression or longitudinal waves can pass through a liquid and they do go through the core. All waves carry energy, and the energy of earthquake waves is easy to observe based on the amount of damage left behind after the ground has stopped moving. Earthquakes can shake whole cities to the ground, performing the work of thousands of wrecking balls. The amount of energy in a wave is related to its amplitude. Large-amplitude earthquakes produce large ground displacements and greater damage.
As earthquake waves spread out, their amplitude decreases, so there is less damage the farther they get from the source. What is the relationship between the propagation speed, frequency, and wavelength of the S-waves in an earthquake? In this animation, watch how a string vibrates in slow motion by choosing the Slow Motion setting. Select the No End and Manual options, and wiggle the end of the string to make waves yourself. Then switch to the Oscillate setting to generate waves automatically.
Adjust the frequency and the amplitude of the oscillations to see what happens. Then experiment with adjusting the damping and the tension. Which of the settings—amplitude, frequency, damping, or tension—changes the amplitude of the wave as it propagates? What does it do to the amplitude? Calculate the wave velocity of the ocean wave in the previous figure if the distance between wave crests is This slow speed seems reasonable for an ocean wave.
Note that in the figure, the wave moves to the right at this speed, which is different from the varying speed at which the seagull bobs up and down. The woman in Figure What is the velocity of a wave whose wavelength is 2 m and whose frequency is 5 Hz? If students are struggling with a specific objective, these questions will help identify such objective and direct them to the relevant content.
When is the wavelength directly proportional to the period of a wave? As an Amazon Associate we earn from qualifying purchases. Want to cite, share, or modify this book?
This book is Creative Commons Attribution License 4. Changes were made to the original material, including updates to art, structure, and other content updates. Skip to Content Go to accessibility page. Physics A microphone converts sound energy into electrical energy in the form of electronic signals. A computer or an oscilloscope can be used to display these electronic signals, which show the same changes in amplitude and frequency as the sound waves.
When these signals are observed on the oscilloscope, the oscilloscope pattern will indicate the same changes in amplitude and frequency which correspond to the wave's loudness and pitch frequency. Volume amplitude — shown by the height of the waves displayed. The larger the amplitude of the waves, the louder the sound.
Pitch frequency — shown by the spacing of the waves displayed. The closer together the waves are, the higher the pitch of the sound. These diagrams show snapshots from oscilloscope traces of three sounds. The speed of sound in air is low, because air is compressible. Because liquids and solids are relatively rigid and very difficult to compress, the speed of sound in such media is generally greater than in gases.
Table Sound, like all waves, travels at certain speeds through different media and has the properties of frequency and wavelength.
Sound travels much slower than light—you can observe this while watching a fireworks display see Figure The relationship between the speed of sound, its frequency, and wavelength is the same as for all waves:.
Recall that wavelength is defined as the distance between adjacent identical parts of a wave. The wavelength of a sound, therefore, is the distance between adjacent identical parts of a sound wave. Just as the distance between adjacent crests in a transverse wave is one wavelength, the distance between adjacent compressions in a sound wave is also one wavelength, as shown in Figure The frequency of a sound wave is the same as that of the source.
For example, a tuning fork vibrating at a given frequency would produce sound waves that oscillate at that same frequency. The frequency of a sound is the number of waves that pass a point per unit time.
One of the more important properties of sound is that its speed is nearly independent of frequency. If this were not the case, and high-frequency sounds traveled faster, for example, then the farther you were from a band in a football stadium, the more the sound from the low-pitch instruments would lag behind the high-pitch ones.
But the music from all instruments arrives in cadence independent of distance, and so all frequencies must travel at nearly the same speed. The speed of sound can change when sound travels from one medium to another. However, the frequency usually remains the same because it is like a driven oscillation and maintains the frequency of the original source.
This simulation lets you see sound waves. Adjust the frequency or amplitude volume and you can see and hear how the wave changes. Move the listener around and hear what she hears. Switch to the Two Source Interference tab or the Interference by Reflection tab to experiment with interference and reflection. Make sure to have audio enabled and set to Listener rather than Speaker, or else the sound will not vary as you move the listener around.
In this lab you will observe the effects of blowing and speaking into a piece of paper in order to compare and contrast different sound waves. Which sound wave property increases when you are speaking more loudly than softly? Calculate the wavelengths of sounds at the extremes of the audible range, 20 and 20, Hz, in conditions where sound travels at The values for v and f are given.
Note that you can also easily rearrange the same formula to find frequency or velocity. Echolocation is the use of reflected sound waves to locate and identify objects. It is used by animals such as bats, dolphins and whales, and is also imitated by humans in SONAR—Sound Navigation and Ranging—and echolocation technology. Bats, dolphins and whales use echolocation to navigate and find food in their environment. They locate an object or obstacle by emitting a sound and then sensing the reflected sound waves.
Since the speed of sound in air is constant, the time it takes for the sound to travel to the object and back gives the animal a sense of the distance between itself and the object.
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